Water level control means



Feb. 24, 1959A- J. D. GooDLAxsoN 2,874,559

WATER LEVEL. CONTROL MEANS Filed Aug. 15, 1955 s sheets-sheet 1 A i 82 Pfl il; 27 i I A l i f A L5 jaa 49 FLl l3/ A g AL i 39 f y/ /0/` Grweuor John Good laxson v J. D. GooDLAxsoN 2,874,559

Feb. 24, 1959 WATER LEVEL. CONTROL MEANS Filed Aug. l5, 1955 5 Sheets-Sheet 2 51 flmmrof lJohn i). Good laxgon Feb. 24, 1959 J. D. GOODLAXSON WATER LEVEL CONTROL. MEANS Filed Aug. 15, 1953 3 Sheets-Sheet 3 Hnvanrot John j). Goolaxou A'normal quantity of water.

United states Parent Or `WATER LEVEL ICONTROL MEANS John D.v Goodlaxson, Colfax, Iowa, assignor to The Maytag Company, Newton, Iowa, a corporation of Delaware Application August 13, 1953, Serial No. 373,956

` q s claims. t (cl. tss- 207) 1The1invention relates to control apparatus and more particularly to control apparatus for a washing machine for initiating a washing operation at various selected liquid levels. f

' llt'isone of the objects of the invention to provide a control arrangement for a washing machine whereby the 'operator may readily manipulate valve' mechanism which automatically modifies the level of liquid within the machine at which the control mechanism is actuated to initiate the washing operation to accommodate for diiferent quantitiesof fabrics to be washed.

` 'Heretoforq in automatically operated washing machines having a tub rotatable about its vertical axis, it has been diicult to provide an effective automatic control means whiclimay be readily adjusted to respond at varying selected liquid levels within the tub for washing correspondingly varying quantities of clothing or fabrics for both the washing and rinsing operations. While various liquid level control means have been preeviously suggested in the form of manually operable switches and the like, most of'these suggestions require the operator to remain at the machine and personally observe or estimate the desired liquid level. At times this is inconvenient and there is always the possibility that the operators estimate of the proper quantity of liquid will be erroneous, with the result that either too much ortoo little liquid may be supplied for proper washing. In addition, the operator must either observe the proper liquid level for the rinsing operation or the rinsing operation is carried out with the In still other arrangements additional switches, oats and the like are required which, of course, adds to the complications and overall cost of the apparatus. i

Inaccordance with the invention, a washing machine having a tub rotatable about its vertical axis is provided withan oscillatable agitator therein which has an upwardly extending hollow center post and a cover or lid is mounted above the tub to cover the same. Carried at the upper portion of the hollow center post is liquid level sensitive 4mechanism capable of transmitting a force corresponding to the difference in level of liquid within the Ytub and the center post to actuate switch mechanism mounted in the lid; This switch mechanism, when actuated, causes the washing `machine to operate in al predetermined Vsequence to wash and rinse the clothingto be treated and to terminate the supply of liquidto the tub.

The hollow center post is provided with a plurality of vertically spaced openings through which air or water may'flow. These openings are adapted to be selectively covered by suitable valve means so that the level of the liquid `at`wh'ich the pressure sensitive mechanism responds mayl'be varied. By closing the` top openings the air trapped within the air column formed 'by the agitator and above the lower openings is relatively large, thus when the level of liquid is still relatively low the head of liquid in the `tub will compress the trapped air in the air chamber to 'actuate the pressure sensitiveV mechanism `at a ice liquid level corresponding to light or low fabric loads. When the upper openings are uncovered the air is, displaced within the air chamber until the upper openings are covered by the liquid. Thus a higher liquid level, is attained and when the liquid` level in the tub exceeds the upper openings a predetermined amount, the pressure sensitive mechanism is operated to actuate the control apparatus to initiate the washing operation and terminate ,the supply of liquid to the tub.

It is, therefore, another object of the invention to provide a washing machine having a tub rotatable about its vertical axis andY with an agitator mounted therein including a hollow center post carrying pressure sensitive mechanism and a plurality of apertures which are covered or uncovered to selectively change the level of liquid within the tub at which the pressure sensitive mechanism responds to accommodate for different quantities of clothing to be washed.

It is yet another object of the. invention to provide an oscillatory agitator with a center post having ,vertically spaced radial openings which are adapted to be selectively covered or uncovered to trap varying quantities of air therein to actuate a pressure sensitive mechanism carried thereby at dilferent liquid levels.

It is still another object of the invention to provide yan agitator having a hollow center post with a plurality of vertically spaced passages that are selectively opened and closed to modify the level at which liquid in a connecting tub will move pressure sensitive mechanism carried in the centerV post for actuating' control mechanismto initiate the Washing operationin a washing machine and to interrupt the supply of liquid thereto.

Other objects, features, capabilities, and'advantages are comprehended by the invention as will;later appear and as are inherently possessed thereby'.

Referring to the drawings:

Figure l is a vertical longitudinal partial sectional view of a washing machine ofthe vertical axis type-having the improved variable liquid level control apparatus applied thereto; l v z Figure 2 is an enlarged vertical sectional view ofthe rotatable tub and improved control apparatus shown,` in Figure l; Y q f v Figure 3 is a horizontal sectional Viewtaken generally on the line 3-3 of Figure 2; V V 1 Figure 4 is a partial sectional view of a modified valve andV flexible diaphragmA construction `for the variable liquid level control openings; and

Figure 5 is a schematic wiring diagram of a control arrangement to which the improvedA apparatus is applicable. f

Referring now in more detail to the drawings for one form of an automatically operated combined washing and drying machine of the vertical axis type, embodying a con# trol mechanism including an adjustable liquid levelfresponsive means made in accordance with theppresent invention, there is shown a base structure V10 which provides a support for an outer stationary containerortub 11, having a bottom wall 12l with a drain'op'ening 13 and a central crowned opening 14 therein, a support for a rotatable inner receptacle .or tub 15u'rnountedsforv Yrotation about a vertical axis and 1having an oscillatory Vagi tator or washing device 16 disposed therein,` aswell `as support for mechanism generallyV referred toV as"'17, for operating the agitator for the washing operation and for rotating the tub in a washingiicycle as will be hereinafter more fully described. o, (l, q i

Enclosing the above mechanism' and secured to'ftlie base 10Vis a `cabinet 18 ywhichfincludes a top vor. cover panelV 19 formed with anvopening V20 ,to permit access to @einen @feeble @ad it is enmity clvsedltrl (i two-piece hollow lid o1* closure 21 having one side hinged at 22 to the top panel 19 to pivot about a horizontal axis.

Extending through the crowned opening 14 are vertical coaxial shaft means in the form of a rotatablefinner 'shaft23 and a rotatable .outer tubular shaft 24 whose vlower end is mounted in a combined radial and-thrust bearing 25 carried by the base and whose upper end supports the rotatable tub 15 within and at the upper portion of the outer tub 11 for lateral movement. The inner rotatable tub 15 includes an outer substantially imperforate cup-shaped portion having a substantially vertical side wall 26 terminating in atop redge 27 disposed above the normal liquid level A desired for washing and a generally horizontal bottom wall 28 formed with a centrally disposed upwardly extending hub 29, and an open-ended cylindrical basket 30 having a lower vperforate portion 31 disposed in substantially parallel lrelation to the imperforate portion to provide a space therebetween forfree ow of the washing liquid out of the receptacle and over the top edge 27 when it is rotated. The basket is secured to the imperforate portion in any suitable manner and its upper portion is imperforate and extends upwardly and inwardly aboveY the top edge 27 terminating to define an opening 32 disposed in alignment with the opening 20 in the cover.

Projecting upwardly from the hub 29 is a vertically disposed oscillatable shaft 33 splined to a mating hub 34 on the agitator 16 for actuating or oscillating the same v about a vertical axis to agitate the material and water therein. Any suitable sealing means 35 may be utilized between the hub 29 and the shaft 33 to provide a fluid tight joint.

Means for oscillating the agitator 16 are provided by suitable mechanism generally indicated at 36, which in this construction, is carried in a gear housing 37 secured to the bottom 28 of the rotatable tub 15 to increase the mass thereof. This oscillating mechanism is preferably directly operated by the inner vertically disposed rotatable shaft 23 which has a driven pulley 38 secured thereto at its lower end, the same being continuously rotated in one direction by a motor 39 through a belt 40. The gear housing 37 is further provided with a downwardly projecting hub portion 41 concentric with the shaft means and is rigidly secured to the upper end of the outer tubular shaft 24 to support the rotatable tub 15.

Since the combined radial and thrust bearing 25 provides the sole support for the krotatable tub 15 which is free to tilt thereabout, centering means in the form of of a plurality of oppositely disposed springs 42 are provided to maintain the tub in a substantially vertical position. These centering springs are disposed at an angle to provide a component of force axially of the shaft means, in addition to the centering action, and each one of their ends connected to the bottom 12 of the stationary tub 11 and the opposite ends are connected to a damper housing 43 journalled on and concentric to the outer shaft 24 and disposed adjacent to and beneath the bottom of .the stationary tub. The damper housing 43 includes fric- Vtion material 44 adapted to engage the crowned portion of the stationary tub to reduce the amplitude of movement of the rotating tub during the extraction operation.

A brake mechanism 45 also carried by thedamper housing 43 is secured in part to the stationary tub 11 and the outer shaft 24 and holds the receptacle 15 stationary during the washing operation and permits its rotation by the shaft means during the spinning operation. The operation of both the brake 45 and a clutch 46 is under control of a solenoid 47 (Figure 5 which when deenergized applies the brake and renders the clutch inactive and when energized releases the brake and engages the clutch to connect the inner and outer shafts 23 and 24, respectively, together to rotate the same in unison.

Y A clutch, centering means, brake and damper mechanisms suitable for effecting the above operation are de- 'scribed in my copending application, Serial Number 66,230, filed December 20, 1948, now Patent Number 2,645,108, issued July '14, 1953, and assigned to the assignee of the present invention. It is to be understood, however, that said application discloses but one form of such mechanism suitable for operating the washing machine as herein disclosed and other suitable types may be utilized. Y

Hot and cold washing liquid or water is supplied from suitable conduits to a thermostatically controlled mixing valve 48 which delivers the water at the proper temperature into a conduit 49 connected to an inlet nozzle 50 for discharging the same into the rotatable receptacle through its upper open end 32.

The agitator 16 disposed within the inner tub 15 is formed with an imperforate flaring basev or body portion 51 extending downwardly and outwardly over the hub 29 to underlie the clothes and has one or more blades 52 extending radially upwardly and outwardly from the upper portion of the base adapted to agitate the liquid within -the tub upon oscillation of the agitator for .effecting .the Washing operation. The lowermost portion of the ,base terminates in a peripheral bead 53 disposed .closely Vadjacent the bottom wall 28 of the rotatable tub which defines a circumferential opening 54 providing communitcation between the interior of the agitator and the surrounding tub.

' The body portion 51 of theiagitator is further provided with an upwardly extending hollow cylindrical center post .or1pedestal 55 disposed `on the vertical axis of the tub which terminates in an upper open end56 above the .normal liquid level A therein. The hollow interior of the agitator provides an inner-chamber or compartment defining an air chamber 57 which has its upper open end closedor sealed by a flexible pressure responsive member or diaphragm58. The cylindrical portion of the center post communicates with the interior of the lower Vportion of the agitator through a suitable opening 59 extending to one side and substantially parallel with the splined portion 34 of the agitator.

The exible diaphragm 58 at the upper open end of the center post is formed from rubber or the like, and comprises a central portion 68 corrugated or shaped in any suitable manner to provide for vertical movement of the same in either direction and an outer annular downwardly directed lip portion 60 which is clamped to the inner periphery of the center post by means of a compressionring or the like 61 to securely hold the diaphragm in position and provide a uid tight seal. Covering and in engagement with the flexible diaphragm 58 is an inverted cup-shaped moveable abutment or member 62 having aan upper generally horizontal flat surface 63 and a cylindrical side wall or skirt 64 which is loosely mounted over the top of the diaphragm and vertically moveable by the same in a manner to be hereinafter described.

In the example shown, the cylindrical side wall of the center post 55 is provided with a pair of vertically spaced openings or passages 65 and 66,'respectively. The lower passage 65 is located adjacent the hub 34 while the passage 66 is disposed above the hub a suitable distance, These passagesrprovide for direct communication between `the tub and thechamber 57 defined by the confines of the agitator. Surrounding the outer periphery of the center post 55 is a shiftable annular resilient valve means or 4member 67 which is moveable vertically from a first position covering and sealing the upper opening 66, as shown in solid lines to a second position, as shown in dot and dash lines, whereat the upper opening Vis uncovered.

Assuming the valve is in *the position jwhereinthe upper-.passage 66 is closed, as liquid is discharged into the tub and its level increases, the liquid level under Ythe agitator is increased .also because the displaced air` at the lower portion of the agitator is discharged through lthe lower open passage '65. When the liquid level reaches and closes or covers the lower passage 65 escape of displaced` air is stopped and rfromthis point on any increase in liquid 'level within the tub increases the static air pressure within thecenter post. As the head of liquid in the tub` increases Awithrespect to that Within the column 57, the air pressure is increased proportionally until it reaches` a value where the diaphragm 58 carrying the cap 62 is elevated thereby fora purpose to be hereinafter more fully described. t

In the washing machine hereindisclosed, the hollow v lid 21 provides a chamberor tcompartment forta plurality of switch assembliesY or devices 69 constituting a part of a control mechanism and includes a handle or grip device 70 which can be Vreadily grasped by the operator to swing the lid into and out of its closed position. The base or lower wall ,section 71 of `thelid is provided with an opening or aperture through which a downwardly directed control button 73 for the switch assembly 69 loosely projects directly above yand preferably in alignment with the (Jup 62 at theA top of the center post. This control button is secured vadjacent one end of a lever 74 which is horizontally pivoted at its opposite'end to a pin.75 `(Figure 5) carried by the lower wall section. A tiltable vbracket 76 mounted `,above the lever 74 on a horizontalpivot 77 provides a pivotal support for a pair of controlmeans or switches78 and 79, respectively, of the mercury type. This bracket is movable about its pivot 77 byfthelever 74 kwhen the; same is moved or elevated bythe liquid level responsive diaphragmSS. Y.

The 'mercury switches are preferably mounted so their longitudinal axes are generally in a horizontal `plane `and have their contacts 80 and 81, respectively,v oppositely disposed, as more clearly shown in Figure 5 of thedrawings. As shown in Figures l, 2"and 5 the button 73 is in its lowermost position indicating that `the yreceptacle is empty or that the liquid is at suchV a low level as to be ineffective to raise the pressure responsivey diaphragm 58. vUnder such circumstances,V the contacts 80 in the switch 78 are bridged by the mercury contained therein, whereas the contacts are not bridged by the mercury in the other switch 79. However, upon the washing liquid reaching a predetermined level in the tub, corresponding .to the setting of'the valve member 67fthe diaphragm 58 is elevated by the air pressure developed by the head of thev liquid 'within the tub and `the button 73 is engaged by the cap'63 covering the diaphragm and the lever is raised upwardly. This upward movement of the lever causes the bracket 76v to rock about `its pivot 77 to theposition whereby the mercury of the switch 78 is moved to the end` opposite the contacts 80v to open the circuit to interruptthellow of water to the tub and the mercury within theother switch 79, is moved to bridge the contacts `81 therein to energize timer motor 82 and the main driving motor 39. i

In order to vary the level of liquid within the tub in accordance with the quantity of fabrics to be washed to provide for more economical'use of'hotv waterand detergent, the valve means 67 encompassing the cylindrical portion of the center post 55 is shifted to one of two positions. As shown, assuming water is being admitted to the tub, as soon as the level of liquid rises above the lower peripheral edge 53 of the agitator 16, all of the air within the contines of the interior ofthe agitator is trapped and from this point on any increase in the liquid level within the tub and the contines of the agitator ,forces the displaced air through vertical passage/5,9 and one of the horizontal passages 65 or 66, either ofwhich may be opened. When the liquid reachesthe highest opening or passage not covered by the` Valve 67, any increase 'in Vthe liquid level within the tub acts to .compress the remaining air in the closed column 57 alike amount. This increased pressure ispappliedzequally throughout and acts against -the lower side of thedaphragm V58e. As `the liquid level in the tub continuesto increase, the pressure on the ,diaphragm increasesi a'v like amount' until it `6 reachesY a point .wherel itovercomes the gravitational weighttofithe capv 62 andthe-natural resistance ofi the flexible diaphragm, after which any increase in liquid level results in a vertical movement of the diaphragm carryingtthe cap. Toward the upper limit ofthe diaphragm travel the cap engagesthe downwardly directed button 73 on the lever 74 and elevates the same to actuate the switch assembly l6,9 as previously described. Since the force required to move the switches is not great and the pressure developed in the air column is in direct proportion to the difference in the level of the liquid within the tub and the column, it can be seen that by properly proportioning the area of the diaphragm 58 it can be made to respond at a relatively low or small difference in level to` actuate the switches to initiate the washing operationand interrupt the supply of water.

' In the position shown with the lower passage 65 open the pressure sensitive mechanism will respond at a relatively low vliquid level B within the tub to initiate the washing operation. `When the valve member isshifted to its ldot and dash line position the upper passage 66 is open and the required level of liquid in the tub to actuate the pressure sensitive member 5,8 will be at its maximum or normal level A.A -It is to be understood that while the drawings merely show a normal and low level position for the water that additional valve means may be provided to provide for an intermediate level or levels to take care of corresponding quantities of clothing to be washed or treated.A Also, that the particular type of valve means may be varied without departing from the spirit of the invention.

In operation, the operator determines if the amount of clothes or fabrics to be washed is equivalent to a full load or somewhat less, whereupon the lid 21 is elevated and the annular valve member 67 is shifted vertically to the low or normal liquid level position as desired. The fabrics to be washed are then placed inthe rotatable receptacle 15, including withit the proper quantity of detergent and the lid is'closed. Thereupon theoperator decides whether to use hot or warm water for the washing operation and adjusts a water ytemperature control knob 83 to position a movable bridging contact 84 in an electrical circuit 85 to either engage a hot water contact 86 in a circuit 87 to energize a hot water valve solenoid 88, or to bridge contact 86 with a warm water contact 89 to simultaneously energize a warm water valve solenoid 91 through a parallel ycircuit 92, when the appropriate cams 93 on drum controller 94 are advancedto complete the circuit from the line L1-L2. For example, if the operator decides to use hot water, the movable bridging contact 84 is moved into engagement withthe hot water contact `86 and the circuit 87 is `conditioned for operation.

Next the operator grasps the timer control knob 95 and turns the same to the desired washing period to properly position the drumcontroller 94 and closes the main line' switch 96 which conditions the timer motor 82 andthe drive motor 39 vfor operation. Upon turning of the timer controlknob, the hot water side of the thermostatically controlled valve is actuated and water at the proper temperature is conducted to the receptacle through the inlet nozzle 50. As the level of the water passes yabove the outer periphery 53 of the agitator, 16 air is trapped within the contines of the agitator and as the water level increasesV therein the displaced air is discharged through the open passage or passages. As the level of water passes above the highest open passage the remaining air is trapped within the air column 57 and is Y cap 62 contacts the .downwardly projecting button 73v which in turn tilts the bracket 76 about its pivot 77 to tilt the pair of mercury switches 78 and 79. At this point the contacts 81 in the mercury switch 79 are bridged to energize the timer motor 82 and the main drive motor 39 through its control circuit and the appropriate cams to start the washing operation by oscillating the agitator 16 through the oscillating mechanism 36 and to advance the cams on the timer, Shortly thereafter the switches are tilted still further by an increase in liquid level and the contacts 80 in the switch 78 are open to deenergize the water supply circuit and cut-off the flow of water to the receptacle, at which time the proper selected quantity of water for the washing operation has been introduced into the tub.

After a predetermined period of agitation during the washing cycle, the timer, through its advancing cams, completes a circuit 97 which energizes the brake solenoid 47 to Arelease the brake 45 holding the receptacle from rotary movement and at the same time causes the clutch 46 to be engaged to directly connect the continuously rotated inner drive shaft 23 to the Vhollow rotatable outer shaft 24 to rotate the tub. Upon rotation of the tub a major portion of the washing liquid is extracted from the fabrics in the tub and discharged over its top edge 27.

At the end of the extraction operation the cam deenergizes the timer and drive motors and the brake solenoid 47 which applies the brake and releases the clutch to stop and hold thevtub stationary. Simultaneously with this action the warm water valve is energized by its cam through a circuit 98 and warm water is admitted to the tub, and upon attaining the selected level therein as determined by the operator in initially selecting the level for the wash water, the switches are tilted in a manner identical to that previously described to again energize the timer and drive motors and interrupt the supply of liquid to the receptacle and to initiate the agitare rinse operation. The operation during the agitating rinse operation is identical to that during the initial washing operation, except that it is of shorter duration, after lwhich the cam -is advanced to interrupt the agitating rinse operation and the tub is again rotated as above described to extractthe rinse water from the fabrics.

At the end of the final extraction operation, the timer motor 82 is deenergized simultaneously with the drive motor 39 and the brake solenoid 47 is deenergized to reapply the brake to the tub to stop the same. The washing cycle is now completed and the operator need only raise the lid 21 and remove the fabrics from the tub. Should the next batch of clothing require more or less washing water the operator merely shiftsV the valve 67 embracing the center post 55 vertically to cover or uncover the passage 66 and the washing cycle willthen be repeated in a like manner when the selectedlevel has been obtained.

Referring now to Figure 4 there is shown a slightly modified form of valve construction applicable to a control arrangement as previously described and since like parts are' given like reference characters a further detailed description of the various elements is not deemed necessary. In this modification a pair of vertically displaced horizontally disposed shafts or bars 107 are carried and journaled by oppositely disposed openings or passages 108 in the cylindrical wall of the center post 55. -The overall length of `these shafts is preferably greater than the diameter of the center post to define end or push button portions 109 to provide the means for selectively shifting the bars in a horizontal plane to one of two positions. One side 110 of each shaft closely fitsv its con.-

tiguous opening and'is provided with -an 0-ring type A- seal v111 to provide apiluid tight joint iri'both positions, while each of the other ends Vlikewise carrying van O-ring seal 111'is adapted to seal its contiguous passage in. one position only. Outwardly from the last mentioned O-ring eaclrshaft 107 'is longitudinally slotted or notched at 112 so that when the knob 109 on this end of the shaft is depressed or moved by the operator into engagement with the post, as shown inthe lower portion of the ligure, the slots provide direct communication between the interior of -the a'irvchamber571and the tub in a manner as prev'iously'd'escribed to control the escape of air and for the same purpose. rlfhus by selectively shifting one or the other" oftheV shafts '107 to open or seal its related passage the level offthe liquid in the tub can be selectively andreadily-varicd to accommodate for different q uantities of fabrics to be washed.

In this particular modification a slightly different diaphragm construction is shown disposed within the confines of the center post 55 and below the upper open end 56. In this instance, the imperforate diaphragm 100 includes an lupper generally horizontal wall 101 and a corrugated or convoluted sidewall 102 terminating in a lower ring portion which is clamped to the interior of the chamber by means of an expansible ring 103 to provide a lluid tight seal. The upper end of the diaphragm is normally spaced 'below the Vupper end of the center post and a movable abutment member 104 having a generally horizontal wall 105 and a cylindrical wall106 with a lower inturned flange loosely tits within the center post and is supported upon the upper end 101 of the diaphragm. During operation, when the diaphragm is elevated by the air pressure, the upper portion of the abutment is moved upwardly out of the open end into contact with the control button. However, it is never completely displaced from the center post and is always guided thereby. Upon a reduction in pressure in the air chamber, the natural resiliency of the diaphragm plus the weight of the abutment member will return both elements to the normal inactive position.

In both modifications it may be desirable under certain design conditions to provide a downward loading on the diaphragm 58 to oppose the pressure developed in the air chamber 57 to provide for proper operation. While no specific loading means has been shown it is to be understood such means would be considered merely a detail as far as the overall operation is concerned.

From the foregoing it can be seen that a simplified valve mechanism for varying liquid levels in an automatic washing machine of the vertical axis type has been provided which is readily accessible to the operator for manipulation to accommodate for varying amounts of weights of fabrics by using proportionately smaller or larger quantities of water to thereby provide for a more economical operation thereof when less than the normal amount of clothes is to be washed. In addition, a simplied diaphragm construction has been provided which eliminates a iioat mechanism.

This application is related to application Serial No. 373,957, iiled August 13, 1953, and Serial No. 374,024, tiled August 13, 1953, both of which are assigned to the same assignee. While I have herein described and upon the drawings shown illustrative embodiments of the invention, it is to be understood that the invention is not limited thereto but may comprehend other constructions, arrangements of parts, details and features without departing from the spirit of the invention.

It is claimed:

l. In a washing machine having a liquid receiving container, an agitator within said container having a hollow center post for'holding air under compression as said container is filled with liquid, an opening in the lower portion of said vcenter post, a movable control member adjacent said agitator, a flexible diaphragm mounted on the top of said center post movable toward and away from said control member in response to changes of air pressure within said center post, a cap member mounted on said diaphragm and movable axially of said center post, and means above said opening for selectively bleeding compressed air from said center post at a plurality of elevational levels of said center post.

Y2. In a washing machine having a liquid receiving container, an agitator within said container having a hollow center post for holding air under compression as said container is lled with liquid, an opening in the lower portion of said center post, a movable control member adjacent said agitator, Va exible diaphragm on said center post movable toward and away from said control member in response to changes of air pressure within said center post, a plurality of escape ports at diierent elevational levels above said opening in said center post for bleeding compressed air from said center post, and means for closing at least one of said ports.

3. In a washing machine having a liquid receiving container, an agitator within said container having a hollow center post for holding air under compression as said container is illed with liquid, an opening in the lower portion of said center post, a movable control member Cil adjacent said agitator, a exible diaphragm on said center post movable toward and away from said control member in response to changes of air pressure within said center post, an escape port above said opening in said center post for releasing a portion of air compressed within said center post by liquid within said container, and means for closing said port.

References Cited in the le of this patent UNITED STATES PATENTS 2,471,778 Ringer May 31, 1949 2,583,077 Arney Jan. 22, 1952 2,605,628 Smith Aug. 5, 1952 2,635,445 Smith Apr. 21, 1953 2,656,431 Bochnan Oct. 20, 1953 

